đą Blue Light Exposure Calculator
Estimate your daily blue light exposure from screens, understand eyeâstrain and sleepâdisruption risk, and get simple changes that protect your eyes and circadian rhythm.
Last Updated: November 2025
Your Blue Light & Screen Strain Score
0 / 100
How your blue light risk score is calculated
We build a 0â100 index from four normalized factors:
- Total screen time: more overall hours raise eyeâstrain risk.
- Evening screen time: screens within 2 hours of bedtime strongly affect melatonin and sleep.
- Brightness & distance: high brightness and close viewing increase light reaching your eyes.
- Protection habits: blueâlight filters and regular breaks lower the score.
Each factor is mapped to a subâscore (0â100, higher = more risk) and combined with an evidenceâinformed weighting model where evening exposure and brightness/distance carry extra influence. This index is educationalâeye health and sleep issues should be discussed with your eyeâcare or medical professional.
Why Blue Light Exposure Matters
Digital screens emit highâenergy visible (HEV) blue light. In normal amounts during the day, blue light helps keep you alert. But heavy screen useâespecially in the eveningâcan contribute to digital eye strain, dry eyes, headaches, and disrupted sleep by delaying your bodyâs natural melatonin release.
This calculator brings together screen time, brightness, distance, and your habits (filters and breaks) to estimate whether your daily exposure pattern is low, moderate, high, or very high risk for strain and sleep disturbance.
Simple Ways to Protect Your Eyes
- Follow the 20â20â20 rule: every 20 minutes, look 20 feet away for 20 seconds.
- Keep screens about an armâs length away and slightly below eye level.
- Use night mode / warm color filters in the evening.
- Dim brightness to match the roomâavoid max brightness in dark rooms.
- Aim for a screenâfree windâdown in the last 60â90 minutes before bed.
Frequently Asked Questions
Does blue light from screens cause permanent eye damage?
Current research mainly links screen blue light to eye strain and sleep disruption, not clearly to permanent retinal damage at typical use levels. However, long hours of closeâup viewing can still cause discomfort, so good habits (breaks, distance, brightness) are important.
How much evening screen time is too much?
Using bright screens in the last 1â2 hours before bed can delay melatonin and make it harder to fall asleep. Many sleep experts recommend keeping screens dim, using a warm filter, or avoiding them altogether in that windowâespecially for children and teens.
Will blue lightâblocking glasses fix the problem?
Blueâblocking glasses may reduce some blue light reaching your eyes, but they donât fix issues like excessive screen time, close viewing, or lack of breaks. Think of them as one tool alongside good screen hygiene, not a magic solution.